1. Field of the Invention
The present invention relates to a Multiple Input Multiple Output (MIMO) wireless communication system. More particularly, the present invention relates to an apparatus and method for inter-cell interference cancellation in a MIMO wireless communication system.
2. Description of the Related Art
In the next generation communication system, also known as the 4th Generation (4G) communication system, research is actively in progress to provide a variety of Quality of Services (QoS) with a data transfer speed of about 100 Mbps. A representative example of such a communication system is an Institute of Electrical and Electronics Engineers (IEEE) 802.16 system. The IEEE 802.16 system employs an Orthogonal Frequency Division Multiplexing (OFDM)/Orthogonal Frequency Division Multiple Access (OFDMA) scheme so that a broadband network can be supported in a physical channel.
In a broadband wireless communication system using the OFDM/OFDMA scheme such as the IEEE 802.16 system, orthogonal radio resources are allocated to Mobile Stations (MSs). Therefore, interference between the MSs is not significant in one cell. However, if a frequency reuse rate is 1, the same band is used in neighbor Base Stations (BSs). Thus, an MS located at a cell's edge experiences interference due to a signal of another MS which uses the same radio resource in a neighbor cell. For example, in a conventional wireless communication system as illustrated in FIG. 1, an MS-A 120-1 receives downlink data by decoding a signal received using a radio resource allocated by a BS-A 110-1. In this case, if the radio resource allocated by the BS-A 110-1 to the MS-A 120-1 is identical to a radio resource allocated by a BS-B 110-2 to an MS-B 120-2, the MS-A 120-1 receives both a downlink signal to be transmitted to the MS-A 120-1 and a downlink signal to be transmitted to the MS-B 120-2. Accordingly, the MS-A 120-1 performs decoding on a mixed signal of the two downlink signals and data reception is not properly achieved. That is, the downlink signal to be transmitted to the MS-B 120-1 acts as interference to the MS-A 120-1.
As described above, in a broadband wireless communication system using the OFDM/OFDMA scheme such as the IEEE 802.16 system, inter-cell interference results in system performance deterioration due to downlink or uplink signals transmitted from different cells but using the same frequency resource or time resource. Accordingly, there is a need for a method for effectively cancelling inter-cell interference.